Identification of cross section in inative mine workings

摘要

A system for identifying the cross section of inactive mine workings, particularly tunnels, uses an arrangement of several ultrasonic sensors (2, 3, 4, 5, 6, 15, 16) linked to a computer (17) on a mobile base. At least three of the sensors (1: 2, 3, 4, 5, 6) are positioned in a spatially fixed relationship to one another to measure the distances in a straight line between imaginary fixed points across the diameter of the tunnel. Actual measurements are taken at a first convenient point for calculating any subsequent measurement adjustments. A second group of sensors (14: 15, 16) is positioned variably within the cross-section, within the reflection or direct beam line, to indicate length. The system in use requires little expenditure on time or man-power and is suitable for areas where personal visibility or space is restricted.